Glossary

A location that use some type of reference system to define it's position on the earth’s surface.

Satellites that detect signals from artificially generated energy sources, then strengthens and emits the signal to its next destination.

A color model that combines emitted light to display color variations.

A formation of data taken, then prepared and combined for processing.

A map that is easy to find patterns or trends with using data.

An item that supports another item.

Combines the spatial extent of two or more layers to create a new output polygon.

A lined data structure that represents linear features, and polygon boundaries, to support analysis functions.

Similar to the function of a line, but are curved.

An arc that connects to surround an area defining a polygon.

Uses slope information to produce output raster images whereby the value of each cell denotes the direction it faces.

Provides the visual impact of the arrangement of the map elements. There are two factors to consider related to the balance: Weight and direction.

Connectors AND, OR, and XOR can be employed to combine the information of two overlying input raster datasets into a single output raster.

The process of creating an output polygon layer containing a zone (or zones) of a specified width around an input point, line, or polygon feature.

Common vector analysis tools used to address questions of proximity in a GIS and can be used on points, lines, or polygons.

Maps that distort area or distance by substituting another thematic variable.

A recommended set of steps that you should follow in order to properly create a map, composed of five steps: define purpose and meaning of the map; choose the scale of the map; determine the map format, printing limitations you may have, and the economics of production and reproduction of the map; abstract and generalize the data; the design and the layout of the map.

The practice of drawing maps.

Encodes a raster by creating records for each cell value by row and column.

The center of mass of a geometric object of uniform density.

A thematic map that uses tones or colors to represent spatial data as average values per unit area.

When you combine observations into a larger group or class to simplify the data so that it can be displayed easier on the map.

A method that is used to extract features from an input point, line, or polygon layer that falls within the spatial extent of the clip layer.

A feature in GIS software that forces nearby lines to be snapped together if they fall within a user-specified distance.

Cyan, magenta, yellow, black; the most common subtractive color model and is occasionally referred to as a "four-color process.”

A visual representation of colors arranged according to their chromatic relationships. Primary hues are equidistant from each other with secondary and tertiary colors intervening.

A vertical arangement of figures or other information.

The arc-node topology for the feature dataset.

This process will require users to input a value by which features are buffered.

Polygons that share an arc are deemed adjacent. The side of each arc can be defined.

Features that are less well defined and exist across space. The most commonly cited examples of continuous features are temperature and elevation.

The state of being strikingly different from something else in juxtaposition or close association.

Colors associated with overcast days. Cool color hues range from blue-green through blue-violet and include the majority of gray variants.

Frameworks that are used to define unique positions.

Represents a region of interest within a geographic context and the surrounding area is cut off often by a neat line.

A thematic map that is an alternative to a choropleth map, but instead of mapping the data so that the region appears uniform, ancillary information is used to model the internal distribution of the data.

Where the map data was derived from.

The spreading of something from one place to another; can relate to the physical movement of people or the spread of disease, or the diffusion of ideas, technology, or other intangible phenomena.

The position of something relative to something else, usually along a line.

Typically a North arrow. The purpose of a directional indicator is to indicate a direction on a map.

Features that are well defined and are easy to locate, measure, and count, and their edges or boundaries are readily defined. Examples of discrete features in a city include buildings, roads, traffic signals, and parks.

Combines adjacent polygon features in a single feature dataset based on a single predetermined attribute.

The degree or amount of separation between locations; can be measured in nominal or absolute terms with various units.

A thematic map that uses a dot symbol to show the presence of a feature or phenomenon; relies on a visual scatter to show a spatial pattern.

A buffer that excludes the input polygon area.

Changeable or interactive representations of the earth. Dynamic mapping refers more to how maps are used and delivered to the map user today (e.g., online, via mobile phone) than to the content of the map itself.

An interruption in the interpretation of statistical data.

Essentially the opposite of a clip. Whereas the clip tool preserves areas within an input layer, the erase tool preserves only those areas outside the extent of the analogous erase layer.

Occurs when inaccuracies are present in the original input and overlay layers and are propagated through to the output layer.

A map that shows fictional locations, usually not scaled to accuracy.

The tendency for the viewer to complete unfinished objects or objects that may be obscured by other elements.

Items that have “thing” qualities and are important to the map.

A region that is disconnected from neighboring regions.

The first feature that should be placed into the map layout. This line is essentially a bordering box that surrounds all the map elements.

The process of resolving conflicts associated with too much detail, too many features, or too much information and data to map.

A process to determine the geographic coordinates of particular street addresses, zip codes, place names, and other geographic data.

The coordinate system that is most commonly used to define locations on the three-dimensional earth; it is based on a sphere or spheroid, and uses latitude and longitude to determine location.

Parallel and meridian lines combined to form a geographic grid system that allows users to determine their exact location on the planet.

Uses computers and satellite imagery to capture, store, manipulate, analyze, manage, and present spatial data. Sometimes referred to as geographic information systems.

Spatially viewing the world, as a geographer.

A computer-based tool used to help people transform geographic data into geographic information.

The study of natural and human-constructed phenomena relative to a spatial dimension.

Specialized software tools used to compare, analyze, or manipulate map layers and their underlying geographic data to create new sets of data.

Satellites that circle the earth proximal to the equator once each day.

To achieve a result by manipulating the boundaries of an electoral constituency.

Determining basic statistical values for the raster as a whole.

A satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense

The symbols vary in size as related to the values they represent.

Uses a graphic element, typically a bar or line, to represent a certain distance on the map.

A visual representation of a coordinate system or location scheme used on the map.

Any circle that divides the earth into a circumference of two halves.

The background or supporting figures on the map.

A title at the top of a section.

Hue, saturation, lightness; based on cylindrical coordinate systems whereby the angle around the central vertical axis corresponds to the hue; the distance from the central axis corresponds to saturation, and the distance along the central axis corresponds to either saturation or lightness.

Hue, saturation, value; based on cylindrical coordinate systems whereby the angle around the central vertical axis corresponds to the hue; the distance from the central axis corresponds to saturation, and the distance along the central axis corresponds to either saturation or lightness.

The dominant wavelength or color associated with a reflecting object.

Also referred to as “minus”, this overlay method creates an output layer with the spatial extent of the input layer, but includes attribute information from the overlay.

Maps derived from satellite images and other photos.

Secondary map areas, each encased within their nearline; often display the primary mapped area in relation to a larger area.

Secondary map areas, each encased within their neat line; often display the primary mapped area in relation to a larger area.

The line determines where the new day begins in the world. It is located 180 degrees longitude from the Prime Meridian, in the Pacific Ocean.

Technique that estimates the value of all unknown points between the known points.

The interrupting of the edge of one object with another object that causes the object to appear on top and closer to the viewer.

This method employs the AND operator.

A thematic map that depicts smooth continuous phenomena such as precipitation or elevation; Also known as contour maps.

A typographic effect that alters the space between adjacent letters in a word.

A complex geostatistical technique that employs semivariograms to interpolate the values of an input point layer and is more akin to a regression analysis.

A word or words used to specify a point on the map; it's purpose is to communicate attribute or ancillary information to the map user.

An angular measurement north or south of the equator relative to a point found at the center of the Earth.

A line that establishes a connection between a location on a map and text.

The vertical distance between lines of text.

Provides users with information about how geographic information is represented graphically.  Usually consist of a title that describes the map, as well as a clear definition of various symbols, colors, and patterns that are used on the map.

Similar to the point-in-polygon overlay, with that obvious exception that a line input layer is used instead of a point input layer.

An operation that requires line features for both the input and overlay layer.

Features composed of multiple, explicitly connected points.

Meant to show actual places with as much accuracy as possible.

A raster output dataset where the output value at each location is a function of the value associated with that location.

A position on the surface of the earth.

A small ancillary map that is at a smaller scale than the map body.

The angular measurement east and west of the Prime Meridian.

A graphic representation of the real world.

The process of moving from the “real world” to the world of maps.

The main focus of the map and should be visually dominant in every case; contains the features important to the message of the map.

Elements of a map may include a neat line, map body, graticule, insets, title, legend, label, ancillary text, ancillary object, scale bar, directional indicator, and metadata.

A representation of Earth’s surface on a flat plane; The methods and procedures that are used to transform the spherical three-dimensional earth into two-dimensional planar surfaces; Mathematical formulas that are used to translate latitude and longitude on the surface of the earth to x and y coordinates on a plane.

The ratio between the distance between two locations on a map and the corresponding distance on Earth’s surface.

A title for the map to be called, and relates to the data being shown.

The primary geographic component of the overall map. The mapped area contains all of the features and symbols used to represent the spatial phenomena being displayed.

The numbers within the aligned cells of the input grids can undergo any user-specified mathematical transformation.

Maps of our environment that are stored in our brains.

Combines features within a layer into a single feature with identical attribute information.

Purpose is to cite the source of data sets used to create the map. Can contain the map author’s information, such as their name, and contact information; should also include the date the map was created and other explanatory information about the creation of the map such as the map projection used.

Statistical bias that can significantly impact the data being shown on a map.

A buffer field that changes width.

How we move through the environments where we live, work, and play; destination-oriented travel.

Border boxes that are placed around individual map elements; must occur within the frame line.

Neighborhood operations examine the relationship of an object with similar surrounding objects.

A common coordinate pair between intersecting lines or polygons.

A location simply defined and described by name.

An arrow on a map telling the reader which way is north.

A device uses a small rotating wheel that records the distance traveled.

The relationship between the directions on the map and the corresponding compass directions in reality.

A vertical photographs that have been geometrically “corrected” to remove the curvature and terrain-induced error from images.

A map of small scale used for general planning purposes.

To lie on top of another.

Lines connecting points of the same latitude.

Reflects the signal from one earth station to other earth station(or stations) without any amplification or retransmission.

In a perceptual group the viewer spontaneously combines elements that share similar properties; elements can be grouped by shape or by size.

A pictorial symbol for a word or a phrase.

This operation requires a point input layer and a polygon overlay layer. A new output point layer is returned that includes all the points that occur within the spatial extent of the overlay.

Zero-dimensional objects that contain only a single coordinate pair.

It is the spatial relationships between adjacent or contiguous features.

A model that stores geographic representations (a series of lines that enclose an area, forming a polygon) as one of its properties.

This operation employs a polygon input and a polygon overlay.

The opposite of the line-in-polygon operation. In this case, the polygon layer is the input, while the line layer is the overlay.

the polygon layer is the input, while the point layer is the overlay.

Shapes created by multiple lines that loop back to create a “closed” feature.

Nearby values of a variable that tend to be similar.

A line of longitude that has a value of zero degrees.

A way to flatten a globe's surface into a plane in order to make a map.

A thematic map that uses symbols of different sizes to represent data associated with different areas or locations within the map.

Symbols for a single, quantitative variable that are sized proportionally to match the data values.

This method divides a raster into a hierarchy of quadrants that are subdivided based on similarly valued pixels.

Refers to the sensitivity of the sensor to variations in brightness and specifically denotes the number of grayscale levels that can be imaged by the sensor.

Group raw data into classes with each class represented by a differently sized symbol.

Data that has not been used or processed.

A map that delivers location information to the map user.

This method utilizes relational operators to evaluate conditions of the input raster datasets.

Location by defining and describing places in relation to other known locations.

The process of gathering data about an area by remotely sensing electromagnetic radiation reflected and emitted from Earth’s surface.

Two numbers are written separated by a colon. The number of the left of the colon represents the distance measurement map and a number to the right of the colon represents distance measured on the ground.

Red, green, blue; The RGB color model combines light beams of the primary hues of red, green, and blue to yield additive secondary hues of magenta, cyan, and yellow.

This method encodes cell values in runs of similarly valued pixels and can result in a highly compressed image file.

The intensity of color. Full saturation results in pure colors, while low saturation colors approach gray — variations in saturation yield different shades and tints.

The ratio between the distance between two locations on a map and the corresponding distance on Earth’s surface.

A bar representing a certain distance on the map; often divided at meaningful intervals to assist the map reader in measuring.

An output layer based on the selection of a particular feature(s) from the input layer.

When you choose a subset of data that you wish to display on the map.

A slight projection finishing off a stroke of a letter in certain typefaces.

Buffer that includes ONLY the input polygon area.

Produced by blocking light, such as by an umbrella, tree, curtain, and so forth. Increasing the amount of shading results in grays and blacks.

Simplifying complex geometric detail so that it looks smoother and appropriate for the scale which you are mapping.

A common error produced when two slightly misaligned vector layers are overlain.

Are made to assess watershed units, inventory forest resources, determine habitat suitability, estimate slope erosion potential, and so forth.

Circles that cut the earth, but not into equal halves.

A somewhat ambiguous and generic term that is used to denote the general geographic area of interest.

A model in which each point is represented as a string of coordinate pairs with no inherent structure.

A hybrid between an attribute operation and a vector overlay operation. It results in the combination of two feature dataset tables by a common attribute field.

The number of pixels utilized in construction of a digital image.

Denotes the ability of the sensor to resolve wavelength intervals, also called bands, within the electromagnetic spectrum.

A spherical, round or circle like shape.

An operation that is used to divide an input layer into two or more layers based on a split layer.

The process of making data uniform, or generalized.

Thick drawn edges that help define an object as a figure.

Involves the mixing of paints, dyes, or inks to create full-color ranges. Subtractive models display color on the assumption that white, ambient light is being scattered, absorbed, and reflected from the page by the printing inks.

A satellite that can synchronize to a near-polar orbit of the sensor with the sun’s illumination.

Dataset that contains an attribute value for every locale throughout its extent.

To use representative shapes, icons, or pictures to represent items or spatial phenomena.

Employs the XOR operator, which results in the opposite output as an intersection.

Cell found in the center of the 3-by-3 moving window.

The amount of time between each image collection period and is determined by the repeat cycle of the satellite’s orbit.

When information is calculated on raster surfaces such as DEMs.

The compactness of the marks that make up the symbol; also referred to as spacing.

Maps concerned with a particular theme or topic of interest, and how things are distributed across space.

A zone where time is measured relative the Coordinated Universal Time (UTC) standard at the Prime Meridian.

The opposite of shade and is produced by adding white to a color.

The name of a map.

A model that is characterized by the inclusion of topological information within the dataset.

Rules that model the relationships between neighboring points or polygons, and determines how they share geometry.

The study of place names and their respective history and meanings.

Preserves all features, attribute information, and spatial extents from both input layers.

The amount of white or black and is often synonymous with contrast.

A premade buffer field within the attribute table to determine the buffer width for each specific feature in the dataset.

A display of data using points, lines, curves, and polygons.

A sentence that describes the relationship of the distance on the ground to the distance on the map.

Each bend along a line or polygon that is not the point of intersect.

Technique that uses the elevation value of cells in a DEM or TIN to determine those areas that can be seen from one or more specific location.

The intellectual plan for the map and the eventual graphic solution that satisfies the plan.

Colors associated with a bright, sunny day. Warm colors are typified by hues ranging from red to yellow, including browns and tans.

Gives the reader geographic references to help recognize landmasses.

A series of surface analysis techniques that define the topographic divides that drain surface water for stream networks.

The integration of the vast amounts of content available on the Internet (e.g., text, photographs, video, and music) with geographic information, such as location.

So-named because its creator, Oswald Winkel, sought to minimize three kinds of distortion: area, direction, and distance. The National Geographic Society has used it since 1998 as the standard projection of world maps.

Distribution in zones or regions, such as zip-codes and area codes for phone numbers.